The Iola register. [volume] (Iola, Allen County, Kansas) 1875-1902, 1887-04-15
HOW Eoos Are CAUSED.
The Interesting Connection Between Fogs
and Dust,

and Dust.
Mr.. John Aitken, fellow of the
Royal Society. has concluded from his
experiments that without dust there
would be no fog, no mist. no cloud, no
rain. He says: IF two large glass
receivers. the one filled with common
air and the other with filtered air, be
connected to q boiler by means OF
pipes. and steam be allowed to pass
into them, strange phenomenon will
be observed. In the former the steam
will be seen as soon as it begins to enc
ter rising in a dense cloud; then a
beautiful white foggy cloud will be
formed, so dense that it can not be
seen through. In the latter there is
nothing to be seen; the eyes may be
strained but no appearance of steam is
to be detected; there is not the slight
est appearance of cloudiness in the re-
ceiver. yet it is as full of water-vapor
rs the other. which continues to be
densely packed with fog. In the one
ease, where there was the ordinary dust
in the air, fog appeared; in the other
case, where there was no dust in sus-
pension, the air remained clear, desti-
tute of fog" Particles of water-vapor
do not combine with each other to form
a cloud-particle. 1t is the fine, invisible
dust i'm the air on which the water-va-
por cOndenses to form the cloud-parti-
cles. When there is abundance of dust
in the air, and little water-vapOr is
present. there is an Over-production Of
dust particles, and the fog particles are
in consequence close-packed. but light
in form, and take the lighter appear
ance of fog; SO that if the dust is in
creased in the air fogs are increased.
If. on the other hand, the particles of
dust are fewer and larger, if the num-
Der of particles be fewer IN proportion
to the molecules of the water-vapOr,
each particle gets weighted, becomes
visible. and speedily falls in mist or rain.
But whence comes this dust? From
many sources. The visible particles
are derived from the breaking up to a
minute degree of the inorganic matter
on the surface of the earth; and the in
visible dust which acts so powerfully
in the production of fogs and clouds is
formed by the breaking up of the dried
spray of the ocean into minute parti-
cles and by the infinitesimal division
of meteoric matter. So fine is this in
visible dust, that. if two thOusandth
part of grain of fine iron wire were
heated. and the dust driven off and
carried by filtered air into Il receiver,
the introduction of steam into the re-
ceiver will ut once occasion an appre-
ciable cloudiness. Common salt is an
active fog-prOducer. and the air is inn
prcgnated with very fine salt-dust.
This is evidenced by the ever-present
sodium line in the spectrum, which ut
one time so troubled spectroscopists.
One source of the supply of this salt
dust is evidently the ocean. The sur
face of the sea, under bright sun.
quietly yields up its waters to be car
ried far and wide by the passing wind.
In these waters is contained dried salt.
when. disguised as fine dust. becomes
a powerful agent in concentrating the
vapor. and displaying the beautiful
of the water. The brine.
which rises with the vapor, pulverized
into fine dust, is an active instrument
in attracting that vapor in the atmos-
phere, and causing the rain to descend
again upon the earth and sea. But
the most active of all surfaces as fog
producer is burnt sulphur. The bril-
liant flame, the transparent flame and
the smoky flame are all fog-producers.
All the present forms of combustion
not only increase the number and
density Of the town fogs, but add to
them evils unknown in the fogs which
veil our hills and overhang our riveys.
In the country the fogs are white and
pure, while in towns they are gray or
dark with smoke. The color of the
suns disk, as seen through High
land fog. is unsullied by impurities;
but in large town it varies from a
light pink to dirty red. according as
it is observed in comparatively clean
part of the town, or in busy, smoky
thoroughfare.
Can fOgs be removed them It seems
hopeless, the writer of the article an
swers, to expect that their frequency,
or persistency. or density can be di-
minished; certainly they can not be
removed. Heat destroys the visible
notes in the air. but flame does not
filtrate it. In fact, if gas is burned in
filtered air, intense fog is produced
when water vapor is introduced. Pro-
duets of combustion from clear fire
and from smoky one give about equal
Jogging. And the air gives more fog
in dry weather than during wet. Nc
doubt the visible particles of dust will
be materially diminished by the re-
moval of the deletcrious and SCOT ele-
ments before the chimney-smoke is al.
lowed to enter the air; this will remove
the '.pea-soup'' character from the
fogs. But it is the sulphur from the
consumed Goals which issuing into the
air. SO rapidly generates the fog by the
quick attraction of the water vapor to
its fine, solid particles. The quantity
of burnt sulphur that escapes into the
air is very great. Seven and a half
million of tons of coal are annually
consumed in London. Now the
average amount of sulphur in
English coal is II per cent. That
would give $3.50 tons of sulphur
burned every year in London fires. II